At present, it is common to utilize air shafts in slitter-corrugators. A shaft is typically equipped with a clamping strip or leaf which can be projected outwardly into clamping engagement with heads on the shaft to hold the heads in the positions to which they have been adjusted for accomplishing various slitting, slotting and scoring operations on sheet material. Accurate positioning is essential in order to produce a proper end product.
When it is desired to readjust or reset the heads, the air pressure on the shafts is decreased to release the clamping pressure on the heads and to enable them to be slid along the shafts to the new positions of adjustment. Thus, typically, an operator will start at one end of a pair of shafts, setting the heads in the proper positions and proceed along the shafts toward the opposite end.
There is nothing at the set-up time to hold the heads in position except the frictional contact with the shafts on which they are mounted.
Frequently, the idle machine is closely adjacent other machines and is subject to the vibrations and shocks created by the operation of such other machines. The vibrating forces and shocks can cause the heads to shift axially along the shafts somewhat. This means that the operator has to go back again, making a second, or perhaps a third check to be sure the heads are all in proper positions before applying the clamping air pressure to the shafts. This is time-consuming and thus expensive.